Insecure object reference - Python

Insecure object reference - Python

Need

Enforcement of proper access controls and authorization mechanisms

Context

  • Usage of Python 3 for writing and executing Python code
  • Usage of Django for building web applications in Python

Description

Non compliant code

        from django.shortcuts import get_object_or_404
from django.http import HttpResponse
from .models import User

def view_user_profile(request, user_id):
    user = get_object_or_404(User, pk=user_id)
    return HttpResponse('User Profile: ' + user.name)

In the code above, the function view_user_profile is vulnerable to Insecure Direct Object Reference (IDOR) attacks.

The function takes a user_id as a parameter from the URL, and uses the get_object_or_404 function to retrieve the User object with the corresponding id from the database. This user object is then returned in the HTTP response.

The vulnerability lies in the fact that there is no authorization check in place to verify if the user making the request has the necessary permissions to view the requested user's profile.

As a result, an attacker could potentially manipulate the user_id parameter in the URL to access the data of other users. For example, if an attacker changes the user_id in the URL from 1 to 2, they could view the profile of the user with id 2, even if they are not authorized to do so.

This is a serious security risk, as it could lead to unauthorized access to sensitive user data.

Steps

  • Check if the user is authenticated before accessing the user profile.
  • Implement a mechanism to verify if the authenticated user has the necessary permissions to access the requested user profile.
  • You can use Django's built-in permissions and authorization system to manage access control.
  • Ensure that the user_id in the request matches the authenticated user's id or the authenticated user has admin privileges before returning the user profile.

Compliant code

        from django.shortcuts import get_object_or_404
from django.http import HttpResponse, HttpResponseForbidden
from .models import User
from django.contrib.auth.decorators import login_required

@login_required
def view_user_profile(request, user_id):
    user = get_object_or_404(User, pk=user_id)
    if request.user.id == user.id or request.user.is_superuser:
        return HttpResponse('User Profile: ' + user.name)
    else:
        return HttpResponseForbidden('You are not allowed to view this profile.')

The updated code now includes a decorator @login_required at the beginning of the view_user_profile function. This decorator is a built-in feature of Django that ensures the user is authenticated before the function is executed. If the user is not authenticated, they will be redirected to the login page.

Inside the view_user_profile function, we added a conditional statement to check if the user_id from the request matches the id of the authenticated user or if the authenticated user is a superuser (admin). If the condition is met, the function will return the user profile. If not, an HttpResponseForbidden will be returned, indicating that the user does not have the necessary permissions to view the requested profile.

This way, we ensure that only the authenticated user can view their own profile or an admin can view any profile, thus fixing the insecure object reference vulnerability.

References